Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus
Provided is an electrophotographic photosensitive member that can suppress the generation of both an interference fringe and a streaky uneven part in a circumferential direction on an image. The generation of the interference fringe and the generation of the streaky uneven part in the circumferential direction on the image are suppressed by defining a length of a line-shaped groove of a support in a circumferential direction, and defining roughness parameters of a support in an axial direction.
1. An electrophotographic photosensitive member comprising a cylindrical support, an undercoat layer and a photosensitive layer in this order, a surface of the support comprising a line-shaped groove in a circumferential direction of the support, wherein
50 μm≤a≤500 μm when a represents a length of the line-shaped groove in the circumferential direction, with regard to 90% or more of the line-shaped groove based on the entirety thereof,
0.7 μm≤ Rzjis
Rsm≤ 50 μm, and
−4.0≤ Rsk≤− 0.2
where Rzjis is a ten-point average roughness, Rsm is an average length of a roughness profile element and Rsk is a skewness according to JIS B 0601:2001 obtained from a roughness profile in an axial direction of the surface of the support.
2. The electrophotographic photosensitive member according to claim 1 , wherein −1.2≤Rsk≤−0.2.
3. The electrophotographic photosensitive member according to claim 1 , wherein
50 μm≤ a≤ 400 μm,
1.0 μm≤ Rzji≤ 1.5 μm and
30 μm≤ Rsm≤ 40 μm.
4. A process cartridge supporting an electrophotographic photosensitive member comprising a cylindrical support, an undercoat layer and a photosensitive layer in this order and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit and a cleaning unit, and being detachably attachable to a body of an electrophotographic apparatus,
a surface of the support of the electrophotographic photosensitive member comprises a line-shaped groove in a circumferential direction of the support, wherein
50 μm≤a≤500 μm when a represents a length of the line-shaped groove in the circumferential direction, with regard to 90% or more of the line-shaped groove based on the entirety thereof,
0.7 μm≤ Rzjis
Rsm≤ 50 μm, and
−4.0≤ Rsk≤− 0.2
where Rzjis is a ten-point average roughness, Rsm is an average length of a roughness profile element and Rsk is a skewness according to JIS B 0601:2001 obtained from a roughness profile in an axial direction of the surface of the support.
5. An electrophotographic apparatus comprising an electrophotographic photosensitive member comprising a cylindrical support, an undercoat layer and a photosensitive layer in this order, a charging unit, an exposure unit, a developing unit and a transfer unit,
a surface of the support of the electrophotographic photosensitive member comprising a line-shaped groove in a circumferential direction of the support, wherein
50 μm≤a≤500 μm when a represents a length of the line-shaped groove in the circumferential direction, with regard to 90% or more of the line-shaped groove based on the entirety thereof,
0.7 μm≤ Rzjis
Rsm≤ 50 μm, and
−4.0≤ Rsk≤− 0.2
where Rzjis is a ten-point average roughness, Rsm is an average length of a roughness profile element and Rsk is a skewness according to JIS B 0601:2001 obtained from a roughness profile in an axial direction of the surface of the support.
6. The electrophotographic apparatus according to claim 5 , wherein the charging units comprise a charging roller disposed so as to abut the electrophotographic photosensitive member, and
a charging unit for charging the electrophotographic photosensitive member by applying direct current voltage only.